All-wave radio receiving system



y 1- J. G. ACEVES 2,243,180

ALL-WAVE RADIO RECEIVING SYSTEM Filed. Jan 19, 1940 INVENTOR Patented May 27, 1941 ALL-W/VAVE RH) RECEIVFNG SYSTEM Application January 19,1940, Serial No. 314,592

11 Claims.

The present invention relates to radio antenna systems and more particularly to an antenna system such that long wave signals (below 2 megacycles) and short wave signals (above 2 megacycles) will be delivered to a suitable radio receiver from one and the same antenna without any switching mechanism in the antenna system; that is to say, with only the operation of the wave band switch normally used in radio receivers that are adapted to receive both long and short wave signals.

The present application is a continuation in part of the co-pending application of Ernest V. Amy and Julius G. Aceves, Serial No. 758,234, filed December 19, 1934.

Heretofore it has been known to receive long wave signals by means of a simple L-type or T- type antenna acting as a capacity exposure pickup means, and it has been recognized that such an antenna provides optimum results for such signals. It has been known also that best results for receiving short wave signals are obtained by means of a doublet type antenna. Also, it has been proposed heretofore to receive both long and short wave signals from one antenna system, but such systems have required special apparatus at both the antenna end and the receiving set end of the down-lead conductors or transmission line, for example, or some other arrangement which has been expensive to manufacture.

According to the present invention, it is possible to deliver to the radio receiver all broadcast signals, from the longest to the shortest, each being received under antenna conditions giving optimum results for the particular signal being received, and the selection of the particular type of antenna function occurring entirely automatically in accordance with the demand or adjustment of the radio receiver, and this is one object of my invention.

It is another object of my invention to provide an antenna system which will function to deliver maximum signal energy over the entire broadcast spectrum with coupling means located only at tenna will function to impress voltages on the radio receiver by either currents circulating between the arms of the doublet or currents flowing in parallel in the down-lead conductors, or both.

It is a further object of my invention to provide an antenna system wherein a doublet type antenna functions as such, or the doublet with its down-lead functions as a T type antenna.

Other objects and advantages of my invention will be apparent from this specification taken in conjunction with the accompanying drawing in which embodiments of the invention are disclosed by way of illustration of the principles thereof.

Figure 1 is a schematic circuit diagram illustrating the principles of my invention;

Fig. 2 is a circuit diagram of a modified form thereof, and

Fig. 3 is a circuit diagram of a simplified form of the system of Fig. 1.

The following definitions are intended in this specification. The term doublet or dipole includes an antenna of at least two arms, however arranged, of equal or unequal lengths and formed from one or more Wires, the arms having a gap (electrical or physical) therebetween to which the down-lead conductors are connected, either directly or through coupling means. The term down-lead includes the various types of multiple conductor transmission lines, whether the conductors are twisted or untwisted, a shielded cable, or a transposed balanced transmission line in which the conductors are spaced apart a fixed distance and periodically transposed. The term transformer includes a construction having two or more coils inductively coupled, or an auto-transformer.

Referring to Fig. 1, there is illustrated a doublet comprising arms H and I2 having a gap l3 therebetween, and a down-lead comprising a pair of conductors i l and [5 respectively directly connected to the arms H and 12 on opposite sides of the gap i3. The down-lead is here illustrated as of the balanced transposed type. At the end ofthe down-lead adjacent the radio receiver [6 is a transformer comprising a primary I! and a secondary I8. The primary [1 is connected across the ends of the down-lead conductors, and the secondary I8 is connected by leads l9 and 20 to the antenna post A and the ground post G,

1 respectively, of the radio receiver It. It will be understood that the radio receiver is of a type to receive and translate both long and short wave signals.

As a convenient arrangement for obtaining electrically the effect of a center tap on the primary winding I1 and for other purposes to be mentioned subsequently, an inductance H is connected across the down-lead conductors l4 and it adjacent the primary H with a lead 22 extending from a center tap on the inductance 2| to the antenna post of the receiver, the leads 22 and [9 being joined as indicated at 23. A fixed condenser 25 is inserted in the line between the junction 23 and the ground post G. The secondary l8 of the transformer may be tuned by a variable condenser 24 .to increase the signal strength, if necessary, in a particular portion of the short wave band.

In one form of the apparatus as described, which was found to give satisfactory results, the primary and secondary windings l1 and I8 were approximately two inches in diameter and consisted of approximately five turns of No. 12 wire and five turns of No. 32 wire, respectively, the primary and secondary being closely coupled; the inductance 2| was approximately sixty turns of No. 32 wire wound on a form approximately one and one-half inches in diameter; the condenser 24 had a capacity range from twenty to three hundred fifty micro-microfarads, and the condenser 25 a capacity of one hundred fifty micro-microfarads.

With such a construction, short wave signals produce circulating currents in the down-lead conductors to impress a voltage on the radio receiver through the action of the transformer, the impedance of the condenser 25 being low at such frequencies. The long wave signals will produce parallel currents in the down-lead conductors which will be delivered to the radio receiver via the inductance 2|, and the conductors 22 and I9. The condenser 25 having a high impedance at such frequencies, and being interposed in the path to ground from the connection 23 prevents by-passing of long wave signal currents through the low impedance secondary I8. Thus, when the wave band switch (not shown) of the radio receiver I6 is adjusted for long wave signals, the doublet ll, l2 and the down-lead conductors l4, l5, will function as a T-type antenna to deliver to the radio receiver the voltages developed between the doublet with its down-leads and ground; and when the Wave band switch is adjusted for short wave signals, the voltages developed between the arms of the doublet will be impressed on the radio receiver, via transformer l'||8.

It is probable that for signals in the band between four and six megacycles, the action of the antenna system in this application is hybrid, that is, in part by doublet action and in part by T-action of the antenna, while signals above and below that band are received respectively by almost pure doublet action and pure T-action.

In Fig. 2 there is illustrated a doublet comprising the =arms 3| and 32 to which the downlead conductors 33 and 34 are connected, across the lower end of which is connected a primary winding 35. In this case, the transformer is shown as a step-up transformer having a secondary 36 one end of which is connected by means of a lead 3! to the antenna post A of the receiving set 38. A center tap on the secondary 36 is connected by means of a connector 39 to the ground post G of the receiver. The entire secondary may be tuned by a variable condenser 40.

A lead 4| extends from a center tap on the primary winding 35 to the lead 31 to the antenna post of the receiver, and has therein an inductance 42 having characteristics such that at high frequencies the impedance of the inductance 42 will be high and thus short wave signals will not reach the antenna post of the receiver directly. At the same time, the re-- actance of coil 42 is suificiently low at long wave: frequencies to permit such signals to reach the: radio set without any appreciable attentuation.. A small condenser 43 is inserted in the lead. 31 in position to insure the impressing of the: full long wave signal currents upon the receiver 38 without being by-passed to ground through: the low impedance secondary 36.

Insofar as the reception of long and short wave signals is concerned, the arrangement of. Fig. 2 will function as described in connection. with Fig. 1. However, the arrangement shown: in Fig. 2 provides reception with a minimum. of noise interference, at least in the short wave: band, such interference being caused by electric motors, vibrators, and various other mechanisms.

Furthermore, by placing the primary winding symmetrically with respect to the ends of the secondary, the capacitative coupling from the primary to each side of the secondary is neutralized. It may be noted that any small deviation from perfect equality of the respective capacities is small in its effect when it is compared with the large circulating current in the tuned circuit 36, 40, which is induced by mag netic coupling with the primary coil 35.

Fig. 3 illustrates the principles of the foregoing circuits, insofar as reception of short and long wave signals from the same antenna is concerned, reduced to a simple form. In this figure, the doublet is illustrated as comprising a pair of arms 5| and '52 having a pair of downlead conductors 53 and 54 respectively directly connected at the upper ends thereof to the halves of the doublet, and at their lower ends to the primary 55 of a transformer. The secondary 56 of that transformer is connected by means of leads 51 and 58 to the antenna post A and the ground post G of a radio receiver 59. A lead 6| extends from a center tap on the primary winding 55 to the lead 51 to the antenna post of the receiver, in which lead is an inductance 62 similar to inductance 42 of Fig. 2. A condenser 63, corresponding to the condenser 25 of Fig. 1 and condenser 43 of Fig. 2, is located on the ground side of the junction of leads 5'! and 6lin this case in the conductor 58, which is on the ground side of the secondary 56. It will be apparent that short wave signals will be impressed upon the receiver through the transformer action, and that long wave signal currents will be impressed upon the receiver through the connector 6|, while the condenser 63, having a high impedance at the frequencies of the long wave signals, Will prevent the short-circuiting of such signals to ground through the sec ondary 56 and its ground connection.

While I have shown and described certain embodiments of my invention, it will be understood by those skilled in the art that modifications and changes may be made in the arrangement and location of parts, and otherwise, without departing from the spirit and scope of my invention, and such modifications and changes are intended to be covered by the appended claims.

I claim:

1. In a radio receiving system, in combination, an antenna having at least a pair of spaced arms, a connection between said arms comprising a pair of down-lead conductors directly joined to said arms respectively, a pair of coils betweenv put to said coils whereby signaling voltages developed between the arms of said antenna in response to signals in one portion of the broadcast spectrum are impressed on said receiver, a connection from said coils to ground, said connection containing an impedance element, and means coupling the same receiver input circuit to said element for impressing on said receiver signaling voltages developed between said antenna with its down-leads and ground in response to signals in another portion of the broadcast spectrum.

2. In a radio receiving system, in combination, a radio receiver having an antenna terminal and a ground terminal, an antenna having at least a pair of spaced arms, a connection between said arms comprising a pair of down-lead conductors joined to said arms respectively, impedance means connected between said conductors at the ends thereof adjacent the radio receiver, means coupling said impedance means to said terminals so that signaling voltages developed between the arms of said antenna are impressed on said receiver, a connection from said impedance means to said ground terminal, said connection containing an impedance element, and means coupling said element to the antenna terminal for impressing on said receiver signaling voltages developed between said antenna with its down-leads and ground.

3. Li a radio receiving system, in combination, an antenna of the dipole type having at least a pair of spaced arms, means connecting said arms comprising a pair of down-lead conductors joined to said arms respectively and a transformer primary winding connected between said conductors, a radio receiver having antenna and ground terminals, a connection from a point on said primary winding to said ground terminal, said connection containing an impedance element, a connection from said antenna terminal to said ground terminal, said connection containing a secondary winding for said transformer and said impedance element.

4. In a radio receiving system, in combination, an antenna of the dipole type having at least a pair of spaced arms, means connecting said arms comprising a pair of down-lead conductors joined to said arms respectively and a transformer primary winding connected between said conductors, a radio receiver having antenna and ground terminals, a connection from an intermediate point on said primary winding to said ground terminal, said connection containing an inductance and a condenser, a connection from said antenna terminal to said ground terminal, said connection containing a secondary winding for said transformer and said condenser.

5. A radio receiving system comprising a doublet antenna, a pair of tightly coupled interference neutralizing coils having a common terminal, a pair of electrically symmetrical lead-in conductors having their upper ends connected across the gap in said doublet and having their lower ends connected to the terminals of said neutralizing coils, a radio receiver having an antenna and a ground terminal, means coupling said coils to said radio receiver whereby a potential diiference is produced across the terminals of said radio receiver due to circulating currents in said lead-in conductors, a connection between said common terminal and a point of ground potential, and means permanently connected in the last mentioned connection for causing said doublet and said lead-in to also act as a capacity exposure signal pick-up means for said receiver.

6. An antenna system for reception of radio signals over substantially the entire range of broadcast signals, comprising, an antenna having at least two portions, apair. of lead-in conductors connected thereto, means connected to said conductors whereby voltages developed between the portions of said antenna may be impressed on a radio receiver, a pair'of connections from said means to said radio receiver for transferring such voltages thereto, said antenna system being grounded, and means also connected to said conductors whereby voltages developed between the antenna with its lead-in conductors and ground may be impressed on said receiver, such means also being connected to said radio receiver connections whereby the latter voltages also are transferred to said receiver.

'7. In a radio receiving system, in combination, an antenna having at least a pair of spaced arms, a pair of down-lead conductors joined to said arms respectively, a radio receiver having an input circuit, and electrically responsive means coupling said conductors to said input circuit so that signaling voltages developed between the arms of said antenna are transferred to said receiver, and other electrically responsive means through which the antenna is grounded and to which the input circuit is connected so that signaling voltages developed between said antenna with its down-leads and the ground are also transferred to said receiver.

8. In a radio receiving system, in combination, a doublet antenna, a pair of conductors having their upper ends connected to said doublet, at step-up transformer comprising a primary having a pair of coils connected to said conductors and a secondary connected to the primary and to the antenna post of a radio receiver, and a connection from said coils to the ground post of said radio receiver, said connection including a condenser.

9. An antenna system comprising a doublet antenna, a pair of down-lead conductors directly connected thereto, a radio receiver having antenna and ground posts, a transformer having a primary connected to said conductors at the ends adjacent the receiver and a secondary connected to said posts, a connection from a midtap on said primary winding to said antenna post, said connection including an impedance, and a connection from the first mentioned connection to ground and containing a second impedance, whereby the system will impress upon said receiver voltages developed between the arms of said doublet and voltages developed between said doublet with its down-leads and ground.

10. An antenna system comprising a doublet antenna, a pair of down-lead conductors directly connected thereto, a radio receiver having antenna and ground posts, a transformer having a primary connected to said conductors at the ends adjacent the receiver and a secondary connected to said posts, a connection from a mid-tap on said primary winding to said antenna post, said connection including an inductance, and a connection from the first mentioned connection to ground and containing a condenser, whereby the system will impress upon said receiver voltages developed between the arms of said doublet and voltages developed between said doublet with its down-leads and ground.

11. An antenna system comprising a doublet antenna, a pair of down-lead conductors directly connected thereto, a radio receiver having antenna and ground posts, a transformer having a primary connected to said conductors at the ends adjacent the receiver and a secondary winding, the transformer being a step-up transformer with the primary winding mounted symmetrically with respect to the secondary, a connection from one end of the secondary to said antenna post, another connection from a mid-tap on the secondary winding to said ground post, a third connection from a mid-tap on said primary winding to the first connection, and a condenser mounted between the junction of said first and third connections and the ground post, whereby the system will impress upon said receiver voltages developed between the arms of said doublet and voltages developed between said doublet with its down-leads and ground free from noise disturbances in at least one phase of its operation.

JULIUS G. ACEVES. 

